Abstract: An implantable device and associated method detect anodal capture during electrical stimulation. A first pacing pulse is delivered using a first cathode and a first anode. A second pacing pulse is delivered using the first cathode and a second anode. A first response to the first pacing pulse and a second response to the second pacing pulse are measured. Anodal capture of the first pacing pulse at the first anode is detected in response to a first difference between the first response and the second response.

Abstract: A system and associated method deliver a respiration therapy. Stimulation pulse trains are delivered to activate a first portion of a patient's diaphragm at an established intended induced respiration rate during a time interval. Stimulation pulse trains are delivered to activate a second portion of a patient's diaphragm at a second rate during the time interval, the second rate being different than the first rate.

Abstract: A system and method for delivering a nerve stimulation therapy determines whether a cardiac EGM signal can be sensed by a bipolar pair of electrodes selected from a number of electrodes positioned for stimulating a nerve. In response to not being able to sense a cardiac signal using the bipolar pair, stimulation of the nerve using a selected pair of the electrodes is enabled.

Abstract: The above-described methods and apparatus are believed to be of particular benefit for patients suffering heart failure including cardiac dysfunction, chronic HF, and the like and all variants as described herein and including those known to those of skill in the art to which the invention is directed. It will understood that the present invention offers the possibility of monitoring and therapy of a wide variety of acute and chronic cardiac dysfunctions. The current invention provides systems and methods for delivering therapy for cardiac hemodynamic dysfunction via the innervated myocardial substrate receives one or more discrete pulses of electrical stimulation during the refractory period of said innervated myocardial substrate.

Abstract: A method includes estimating a cardiac signal of a patient, estimating a length of a cardiac refractory period based in part on the cardiac signal and selectively adjusting the length of phrenic nerve electrical stimulation to be delivered to the patient based on the estimated length of the cardiac refractory period. In some examples the method includes delivering phrenic nerve stimulation for approximately the entire refractory period. The phrenic nerve stimulation may be used to treat a variety of breathing disorders.

Abstract: Techniques are described for detecting conduction abnormalities in a heart of a patient. In particular, an IMD may be configured to obtain electrical signals corresponding to cardiac activity of the heart of the patient and periodically analyze a most recent electrical signal of the obtained electrical signals to detect an electrical conduction abnormality of the heart. The IMD adjusts a frequency at which the most recent electrical signal is analyzed based on at least one physiological parameter of the patient. For example, the IMD may increase the frequency at which the most recent electrical signal is analyzed when a heart rate parameter has significantly changed and the number of detected premature ventricular contractions (PVCs) is greater than or equal to a threshold number. In this manner, the most recent electrical signal is analyzed at a higher frequency in situations in which conduction abnormalities are more likely.

Abstract: The above-described methods and apparatus are believed to be of particular benefit for patients suffering heart failure including cardiac dysfunction, chronic HF, and the like and all variants as described herein and including those known to those of skill in the art to which the invention is directed. It will understood that the present invention offers the possibility of monitoring and therapy of a wide variety of acute and chronic cardiac dysfunctions. The current invention provides systems and methods for delivering therapy for cardiac hemodynamic dysfunction via the innervated myocardial substrate receives one or more discrete pulses of electrical stimulation during the refractory period of said innervated myocardial substrate.

Abstract: The present invention provides an apparatus and method for monitoring muscle function based on an index derived from a pressure or force signal. The muscle function index is derived from an instantaneous muscle stiffness ratio computed as the ratio of the first time derivative of the pressure or force waveform to the corresponding instantaneous pressure or force. The instantaneous stiffness ratio, ?/E(t), is in units of 1/sec and relates to the rate of strong bond formation and will be influenced by calcium handling properties of the muscle fibers and the intracellular calcium concentration. As such, an index derived from ?/E(t) provides a measure of the inotropic status of the muscle.

Abstract: The operation of an implantable medical device executing at least one set of firmware code is modified using a hardware/firmware trap at a point of execution of the set of firmware code. A patch code for directing the implantable medical device to perform a particular task is provided for execution when the trap generates an interrupt. The operation thereafter returns to the point of execution of the set of firmware code where the interrupt was generated and execution of the set of firmware code continues in a normal manner.

Abstract: An extra-systolic stimulation (ESS) therapy addresses cardiac dysfunction including heart failure. ESS therapy employs atrial and/or ventricular extra-systoles via pacing-level stimulation to a heart. These extra-systoles must be timed correctly to achieve beneficial effects on myocardial mechanics (efficacy) while maintaining an extremely low level of risk of arrhythmia induction and excellent ICD-like arrhythmia sensing and detection (security). The present invention relates to therapy delivery guidance and options for improved ESS therapy delivery. These methods may be employed individually or in combinations in an external or implantable ESS therapy delivery device.

Abstract: Techniques and apparatus for estimating the temporal refractory period of a heart, for adjusting a parameter for delivery of extra-systolic stimulation (ESS) therapy and for detecting an arrhythmia during delivery of ESS therapy In some aspects, probe pulses are periodically delivered to estimate the location of the end boundary of the refractory period, and accordingly estimate its length. In some embodiments, the parameter is adjusted based on estimated length of the refractory period. For example, an extra-systolic interval (ESI) for delivery of ESS is adjusted to be a fixed interval longer than estimated lengths of the refractory period. In other aspects, the parameter is adjusted based on a measured delay (or latency) between delivery of an ESS pulse and detection of an evoked response resulting from the pulse. Also, delays between delivery of an ESS pulse and detection of a subsequent depolarization are monitored to detect an arrhythmia.

Abstract: The present invention relates to the secure delivery of an extra-systolic stimulation (ESS) therapy to treat cardiac dysfunction that employs atrial and/or ventricular extra-systoles via pacing-like stimulation of the heart. These extra-systoles must be timed correctly to achieve beneficial effects on myocardial mechanics (benefit) while maintaining an extremely low level of risk of arrhythmia induction and excellent ICD-like arrhythmia sensing and detection (security). Further experience with ESS has led to improved implementation methods that depend on better blanking, ESS stimulation timing (of an “extra-systolic interval” or ESI), and ESS therapy delivery options and guidance. These methods may be employed individually or in combinations in an external or implantable ESS therapy delivery device.

Abstract: A method and an apparatus for synchronizing clock domains. A slow clock signal is received. A circuit in a slow clock domain is operated based upon the slow clock signal. A fast clock signal is received. The slow clock signal is synchronized using the fast clock signal. The operation of the circuit is modified from the slow clock domain to the fast clock domain, modifying the operation comprising changing a clock operation frequency during a non-transition period of the slow clock.

Abstract: A method and an apparatus for a hardware/firmware trap. At least one set of a firmware code is executed for operation of the device. Modification to the operation of the device is performed. The modification to the operation comprises: receiving a patch code; creating a firmware trap; generating an interrupt in response to the firmware trap; and executing the patch code in response to the interrupt.

Abstract: An implantable system and method are provided for detecting myocardial electrical recovery time and for controlling the delivery of cardiac stimulation pulses relative to the detected recovery time. One or more fiducial points on a T-wave signal sensed from one or more intracardiac EGM or subcutaneous ECG signals are detected for estimating myocardial recovery time. Extra systolic stimulation pulses are delivered at an extra systolic interval based on a detected recovery time to effectively produce post-extra systolic potentiation while preventing delivery of extra systolic stimuli during the vulnerable period.

Abstract: A system and method are provided for controlling extra systolic intervals during extra systolic stimulation delivered to effectively produce post-extra systolic potentiation (PESP) to improve hemodynamic function for the treatment of cardiac mechanical insufficiency. Controlling the interval is based on measurements of the electrical restitution properties of myocardial tissue. A parameter related to the action potential duration is measured from an electrical signal received from the heart during extra systolic stimulation at different intervals. An electrical restitution condition is determined from the measured action potential duration related parameter. An operating interval is set based on the measured electrical restitution. Methods for controlling the interval further include setting the operating ESI based on electrical restitution and/or the mechanical effect of PESP on post-extra systoles.

Abstract: An improved turning point system and method for performing data compression is disclosed. The system improves the conventional turning point compression method by selecting a predetermined number of the “best” turning points in the sample window including data samples X0 and XN. From this sample-window, ones of the data samples X1 through X(N−1) will be identified as turning points using a selected one of a disclosed set of turning point detection methods. In one embodiment, a turning point is identified by determining that the slopes in the lines interconnecting adjacent data points have different polarities. In an alternative embodiment, a data sample XM is considered a turning point if the slope of the line between the data samples XM and X(M+1) has a different polarity as compared to the slope of the last waveform segment that was encountered that did not have a slope of zero.

Abstract: A method and an apparatus for synchronizing clock domains. A slow clock signal is received. A circuit in a slow clock domain is operated based upon the slow clock signal. A fast clock signal is received. The slow clock signal is synchronized using the fast clock signal. The operation of the circuit is modified from the slow clock domain to the fast clock domain, modifying the operation comprising changing a clock operation frequency during a non-transition period of the slow clock.

Abstract: The present invention permits discrimination between evoked response signals and post-pace polarization signals sensed by an implantable medical device by noting the polarity of the positive or negative change in voltage in respect of time (or dv/dt) of the waveform incident on the lead electrodes during a short period of time immediately following a paced event. It has been discovered that the post-pace polarization signal exhibits a relatively constant polarity during the capture detect window, and that the evoked response signal may cause the polarity of post-pace polarization signal to reverse during the capture detect window. The sign of the post-pace polarization polarity, either positive or negative, is determined by the design of the specific output circuitry. The evoked response signal may, reverse the polarity of the sensed signal in either case, from positive to negative or from negative to positive, during the time window of interest.

Abstract: A method and an apparatus for a hardware/firmware trap. At least one set of a firmware code is executed for operation of the device. Modification to the operation of the device is performed. The modification to the operation comprises: receiving a patch code; creating a firmware trap; generating an interrupt in response to the firmware trap; and executing the patch code in response to the interrupt.